As mentioned in Resolution A.817(19) of IMO, Performance Standards of ECDIS,
“Electronic chart display and information system (ECDIS) is a navigation information system which, with adequate back-up arrangements, can be accepted as complying with the up-to-date chart required by Regulation V/19 of the 1974 SOLAS Convention, by displaying selected information from a system electronic navigational chart (SENC) with positional information from navigation sensors to assist the mariner in route planning and route monitoring, and by displaying additional navigation-related information if required. “
In simple terms, ECDIS is a computer-based navigation system that complies with IMO Regulations and can be used as an alternative to paper navigation charts. By integrating a variety of real-time information, it is an automated decision aid capable of continuously determining a vessel’s position in relation to land, charted objects, navigation aids, and unseen hazards.
ECDIS Consists of:
The HARDWARE of ECDIS is generally a computer with Graphics Capabilities, a higher performance PC or a graphics workstation installed in a console integrated/ linked with other items of ship’s equipment.
Thus, ECDIS obtains,
- the course from Gyro Compass
- The rate of turn from Rate of Turn Indicator
- The speed through water from ship’s Speed Log
The key features are the links with the position sensors of the ship (transit satellite navigation system) and in particular with the GPS (Global Positioning System, a satellite-based positioning system), supplying via the NMEA interface a constant stream of highly precise position data (NMEA, National Marine Electronics Association; NMEA0183 Standard for Interfacing Marine Electronic Devices, data record), Even RADAR pictures can be superimposed, either as raw data from raster-scan radar, or as synthetic ARPA RADAR information.
The Hardware should be of type-approved and comply with the guidelines of the International Electro-technical Commission.
The SOFTWARE of ECDIS should be as per IMO Performance Standards (Res A817(19)). It consists of the User Interface and the so-called ECDIS Kernel, a software that makes it possible to read the data and display a chart. This software is also called “Function Library”. In addition to the chart picture, the user interface shows buttons and keys for handling the charts.
Table of Contents
ENC (Electronic Navigational Chart), there are two different types of electronic charts in use with ECDIS and all navigational officers and marine managers should be aware of their differences and limitations. These types are:
- ENC Charts
- Raster Charts
What is ENC Chart?
ENC (Electronic Navigational Chart), also called ‘Vector Charts’. Vector Charts are layered with digital information that enables mariners to electronically interrogate features on the charts such as buoys, Navigational Marks, Traffic Separation Schemes (TSS), and Safety Contours with detailed information displayed for the user.
ENCs enable users to set different types of navigational Alarms to act as a warning to the mariner. These warnings are usually visuals as well as audible to give a clear indication of any dangers lay ahead. The navigational alarms include hazards such as shallow depths, shoals, and isolated dangers as well as minimum under-keel clearance, like an anti-grounding alarm, provided that the ship’s Echo Sounder is integrated with the ECDIS, draught details and alarms parameters specified.
Early warning alarm of approaching way-points, and alteration of the course points and Position-fixing reminders and changing electronic chart alarm can also be specified within the alarm parameters.
The ENCs provide mariners with a clear display of the navigational situation without distorting the chart display while reducing the chart scale. ENCs must conform to IHO S-57 Standards.
What is a Raster Chart?
These are the charts that are produced by converting paper charts to digital images by using scanners. These images are similar to digital camera pictures, which could be zoomed in for more detailed information as it does in ENCs. IHO Publication S-61 provides guidelines for the production of raster data IMO Resolution MSC.86(70) permits ECDIS equipment to operate in Raster Chart Display System (RCDS) mode in the absence of ENC.
The IHO has issued a circular warning that ECDIS may not display some isolated shoal depths when operating id ‘base’ or ‘standard display’ mode. As a result, passage planning and monitoring alarms may not always be activated when approaching such dangers and may result in grounding.
Mariners must ensure that their ECDIS display has been set-up properly to the circumstances and conditions so that it includes all information necessary for safe navigation. ECDIS display modes that are set-up in ‘base’ display mode may remove vital information.
Advantages of ECDIS over Paper Charts:
- Real-time Navigation and Continuous Monitoring: Gives the actual position of the ship, which increases situational awareness. Paper Chart gives the ship’s position only when you plot it. Imagine plotting positions on Paper Charts while in Canakkale Strait or Singapore Strait.
- Easy to Update: You might remember when the ship gets alongside at the port and ship’s agent comes with a bundle of NTM’s and Navigating Officer used to update the Charts and Publications. Hectic, isn’t it? That all is past now. With ECDIS, the Navigating Officer receives weekly updates via Email which he downloads and uploads them to the ECDIS. Even the T&P notices can be updated electronically on the ECDIS.
- Availability of Charts: Ship’s Agent used to come on-board not only with NTMs but charts for the next voyage, if it is a new voyage and charts are not present on-board, and if not then start the voyage without some of the voyage charts as they were provided during the voyage. With ECDIS, Navigating Officer just requests the charts not programmed in system and upload them after receiving, with latest updates.
- All-in-One Information: Integration of all the navigation equipment in ECDIS, gives you all the required information on ECDIS Display. GPS position, Depth, Draught, information of targeted vessels, etc. are all available at one glance.
- Enhances Search and Rescue Capabilities: With integration on NAVTEX, GPS, and EGC, ECDIS can all types of warnings and alerts can be displayed on ECDIS Screen.
Over-reliance on ECDIS when using ENC data may prove dangerous when inadequate training and familiarization has been given. Unfamiliarity with the ENC data and ECDIS functionality may cause operator error.